1. Field of the Invention
The present invention relates to a flat coreless vibrator motor using magnetic latching power suitable for use as a silent alert source for a small, portable communication device such as a radio pager or a portable telephone or a vibration source for a massager.
2. Description of the Related Art
A conventional flat coreless vibrator motor is disclosed in U.S. Pat. No. 5,036,239.
The flat coreless vibrator motor where a number of, for example, three armature coils 99 are eccentrically arranged is popular in the market since it is possible to control the amount of eccentricity of the center of gravity of a rotor to be large. However, it costs much to manufacture the flat coreless vibrator motor of the three coil type since there are three coils. Also, as shown in U.S. Pat. No. 5,036,239, in the flat coreless vibrator motor of the three coil type, all the coils contribute to the production of torque during a rotation for only an extremely short time and, in general, current flows through only two coils according to the principle of the rotation.